Chad Reed (left) and James Stewart collide while racing for the lead on the last lap of Saturday's Supercross event at the Georgia Dome in Atlanta.

But the grand finale was more explosive than the Kawasaki rider expected — as was his ensuing top spot on the podium.

"It's definitely a gift, and I'll take it," Villopoto said after his third win of the season and 12th of his career. "I knew something was coming. I didn't know it was going to be to that extent."

The latest white-hot battle between Reed and Stewart — one of the best rivalries in motor sports — reached another flashpoint before 69,517 at the Georgia Dome.

After capitalizing on a mistake by Reed on the penultimate lap, Stewart was leading entering Lap 20. But Reed countered with an aggressive move for first on the turn preceding the whoops section.

The riders collided and went to the dirt. By the time, they re-fired their bikes, Villopoto and runner-up Ryan Dungey's Suzuki had whizzed past.

Reed, who hung on for third after leading 16 laps, tried to stop Stewart on the cooldown lap to hash things out. Stewart motored away after only a few words.

"There's two sides to every story, and I'm sure he feels I totally cleaned him out," Reed said. "I wanted to say, 'Hey, I tried to just put it to the inside, and you had the option to let me by or run into me,' and he chose to run into me. He didn't want to talk."

The Australian then paused to smile.

"I think our relationship will go back to what it's always been," he said.

Both two-time champions, Reed and Stewart have been Supercross' most entertaining feud the past five years. In 2010, they both were injured after colliding in the second race (Stewart had season-ending surgery a few weeks later; Reed would miss most of the year). In the past, Reed has said he dislikes Stewart personally, and their 2009 title fight included allegations of foul play that resulted in a suspension for Stewart's teammate.

But they had appeared to mend fences this season, with Reed admitting Saturday morning that he recently had provided Stewart with advice on ownership, adding they "have respect for each other" because each owns a majority stake in their teams.

They seemed to play nice for 19 laps Saturday night. Stewart took the holeshot and led the first two laps before slipping entering the rhythm section.

Reed took the point for the next 16 laps under mostly heavy pressure from Stewart, who stumbled again exiting the whoops on Lap 14.

He made up the two-second gap quickly on his Yamaha, though (getting help when Reed lost time passing the lapped Kawasaki of Chris Blose), and was positioned perfectly entering the final corner of Lap 19. As Reed approached the lapped Yamaha of Kyle Regal (Stewart's teammate), he swung his Honda to the high side following Regal. Stewart went inside for the lead.

"That was my own fault, just found myself on the wrong side of a lapper," Reed said. "The lapper tried to get out of my way, and I should have put myself inside. Just my mistake. Just found myself at the wrong place, wrong time. Just disappointed I threw that one away."

Reed was seeking his second consecutive victory and said last week's San Diego win brought momentum. He posted the second fastest lap in practice Saturday — the first time his TwoTwo Motorsports organization (which was formed hastily in the offseason and lacks major sponsorship) had shown such speed in prerace.

"I just had a great week," he said. "I'm happy. I'm content. I know I was in the fight and had a shot at it. It was my mistake. I can live with that."

Tougher to stomach might be the impact on Stewart.

"He ran a great race, and it sucks to end like that," Reed said.

Stewart didn't speak to reporters after the race but did post a postrace video on his website in which he addressed the crash.

"I rode my best," he said. "At the end of the day, that's all I can do. ... That's not racing. I apologize to the fans and my whole team. I was trying hard. We'll go next week. The quote of the week: That was a racing incident. We'll see. We'll come back next week. I'm all healthy. My attitude's good. I feel strong."

Reed wasn't apologizing for taking a shot at a win that would have meant a lot to a team he's funding largely out of his own pocket.

"This is a championship that pays millions of dollars," he said. "(Stewart) was aggressive. I gave it back to him. Unfortunately, we both went down. I want to win and got to do what I've got to do.

"I tried to talk to him. He was being pretty respectful (during the race). I guess that's why I tried to stop (him) at the end. It's a long series with a lot of racing to go, and we kind of got caught up in our own little battle tonight. We were 1-2, easy. We ended up 3-4. With the championship on the line, the guy who won got a lot of points on us tonight. It's not what either of us wanted."

Next week's event at Daytona Beach, Fla., will mark the halfway mark (round nine) of the 17-race season, and Villopoto has opened up a 10-point lead on Stewart (who trailed by three entering Atlanta). Reed is 21 points behind in third, followed by Trey Canard (who rebounded from a spill to take fifth Saturday) 25 points behind. Dungey is 26 points behind in fifth.

It was no surprise the top five in points also were the top five finishers on a night of treacherous conditions. Villopoto said the Georgia clay was unusually hard-packed Saturday, and he had made a few minor errors himself while riding third most of the race. The win might bode well — the past two winners of the Atlanta round (Stewart and Dungey) have gone on to the championship.

"Getting through here with a win is awesome," he said. "It's a blessing for sure. I'll take them. It's racing, and that's what happens sometimes."

In the Supercross Lites event, Dean Wilson triumphed after Blake Wharton crashed out of the lead with four laps remaining. Justin Barcia finished second, followed by Blake Baggett. Wilson and Barcia are tied for the points lead in the Eastern Regional division.

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